Rolling mill



Aug, 2, 193.8. A'. NORTON y 2,125,585

l ROLLING MILL Filed June 28, 1937 9 sheets-sheet 1 l ug., 2, 1938. A.NORTON l ROLLING MILL Filed June 28, 1937 9 Sheets-Sheet 2 v Aug; z,1938. y A NORTON 2,125,686

ROLLING MILL Filed June 28,' 1937 9 Sheets-Sheet 3 Aug. 2, 1938.. A.NRTON 2,125,686

ROLLING MILL Filed Jun 28, 195'? 9 sheets-sheet 4 A, NORTON ROLLING MILLAu@ 2, 193@l Filed June 28, -195'7 9 Sheets-Sheet 5 NORTON ROLLING MILLFiled June 2B, 193'? 9 Sheets-Sheet 6 Aug. z, 193s..

A. NORTON RoLLNG MILL Filed Junge 28, 193'? 9 Sheets-Sheet 7 A. NORTONROLLING MILL Aug.. 2, 1938.

Filed June 28, 1957 9 Sheets-Sheet 8 A.NORTON ROLLING MILL Aug. 2,1938.,

9 shets-sheet 9 Filed June 28,` 1937 @Hmmm fir-u Patented Aug. 2, 1938UNITED STATES lROLLING :MILL

Albert Norton, Birmingham, England, assigner to Tube Products Limited,Oldbury, Birmingham,

England rApplication June 28, 1937, Seri-al No. 150,817 In Great BritainJuly 4, 1936 l2 Claims.

This invention has for its object to provide an improved machine foreffecting reducing operations on metal tubes or rods.

The invention comprises the combination of 5 die rollers forming thepass through which the work piece is to travel, driven supportingrollers which also serve to rotate the die rollers, and means foreffecting reciprocatory movements of f the die rollers relatively to thework piece and Vsupporting rollers..

In particular the invention comprises the combination of' die rollers, areciprocatory carriage on which the die rollers are mounted, drivensupporting rollers formed around their -peripheries with alternatelyarranged working surfaces and ats or the like, andmeans acting on thecarriage for imparting rearward movements to the die rollers when theycoincide with` the iiats or the like on the supporting rollers, themovements of the die rollers and' carriage in the Iorward directionbeing effected, when the machine is in operation, by the action oftheworking surfaces of the supporting rollers on the die rollers.

which each is formed with a peripheral groove, the width of -whichprogressively varies from a narrow part corresponding approximately withthe diameter to be produced on the work piece to a relatively wide partcorresponding approximately with the 'original diameter of the workpiece.

' Also the inventioncomprises a pair of die rollers as above describedeach of which is pivotally connected at a convenient radial position toone end of a link, and the other end ci each of the two linksl beingpivotaliy attached to a spring loaded member, the purpose of the linkageand spring being to maintain the dle rollers in proper co-relationship.

, In the accompanying sheets ofexplanatory drawings- Figures l, 2 and 3arediagrams illustrating in diiIerent positions tube reducing rollersoperat-A ing in accordance -with the invention.

and plan ci a tube-reducing machine embody-l ing my invention. v

Figure 6 is a sectional side elevation and Figure 'I a sectional frontelevation of the die rollers, the supporting rollers, and theirimmediately associated parts, Figure 7 being taken on the line,A.AFigure 4.

' Figure 8 is a sectional end elevation ofthe tube feeding mechanism,this vview being taken Further the invention comprises die rollers ofFigures 4 and 5 are respectively side elevationv on the line C.C Figure9. Figure 9 is a cross section on the line BB Figure 8.

Figure 10 is a part sectional side elevation of a portion of themechanism situated between the tube reducing rollers and the feedingmecha- 5 nism.

All the views shown in Figures 6 to 10 are Yshown to a larger scale thanFigures 4 and 5.

Referring to Figures l to 3 I have there illustrated diagrammaticallythe supporting and die 10 rollers used'in a machine embodying myinvention, for reducing the diameter and thickness of a cold steel orother metal tube. The pass for the tube is formed by a pair of dierollers a. Each'die roller is formed with a circumferential groove.Preferably this groove is made oi vary'- ing width, so that itprogressively increases in width from a narrow part which isapproximately the same diameter as that to be produced on vthe tube, toa relatively wide part which is of approximately the same diameter asthe o'riginal tube. This variation 'oi width is clearly shown in Figure7. The inactive portion of each die roller which Joins the adjacent endsof the wide and narrow parts of the said groove is formed by a atorrecessed part b. Thetwo die rollers are mounted on a carriage (notshown in Figures 1 to 3) which can reciprocate in the direction ci theaxis of the tube. The details of the carriage and the means for holdingthe two die rollers in the proper working relationship `will bedescribed later.

The die rollers are arranged between a pair of supporting rollers c.These are of lconsiderably larger diameter than the die rollers and aregeared together. Also the supporting rollers are driven from anyconvenient source of motion. On looking at Figures l to 3 (also Figures6 and 7) it will be seen that the peripheral portion of each roller cwhich bears on the adjacent die rollera is formed by an alternatingsuccession Y oi parts d, e. Each part d forms a portion of thecylindrical surface oi the roller, and is herein termed the workingsurface. Each part e, which is made of Aany convenient length and isusually rather greater than the part d, is iiat, or recessed. The dierollers a are free to rotate about their axes on their carriage and aredriven by the working surfaces d of the supporting rollers c.

The tube g to be reduced in diameter and wall thickness is supportedinternally byva mandrel h, this being secured to one end of a rodwhichextends backwards through the tube and is attached at its rear end`to the frame of the machine.'

Starting with Figure 1, the die rollers a are shown in the positionwhich they occupy at the beginning of each of the successive reducingactions on the tube, and the forward end of the tube is shown in thereduced condition to which it has been brought by previous actions ofthe said die rollers. 'I'he initial condition of the tube is shown atthe right hand side of the vertical centre line of Figure l, and thefinished condition at the left hand side. In the relative positions ofthe supporting rollers c and the die rollers a shown in Figure 1, a.working surface d on each supporting roller has just entered intoengagement with the outer periphery of the adjacent die roller, and thebeginning of the working surface of each die roller rests upon the outeroriginal surface of the tube. Due to the rotation of the supportingrollers and the frictional engagement of the parts d of the supportingrollers with the peripheries of the die rollers the latter are not onlyrotated but are also caused to move laterallyto the left relatively tothe stationary tube g, this lateral movement of the die rollers beingalso transmitted by the die rollers to the carriage on which they aremounted. During this movement the die rollers are, in addition, pressedtowards -each other and are caused to exert a squeezing action on thetube for effecting the required reduction of diameter and thickness. Therelative positions occupied by the supporting and die rollers at aboutone half of the length of the travel of the die rollers are shown inFigure 2. This action continues until the parts d of the supportingrollers pass out of contact with the die rollers. 'I'his condition isshown in Figure 3 which shows the relative positions of the supportingand die rollers at the end of the travel oi the die rollers. Immediatelyafterwards the pressure exerted by the supporting rollers on the dierollers is released, due to the fact that the flats e come adjacent tothe die rollers, and consequently the carriage on which the die rollersare mounted is free to be returned quickly to the initial position shownin Figure l, under the action of a spring or weight or other convenientmeans, the initial position being determined by any convenientlyarranged stops. During this movement the die rollers move apart byrolling up the tapered part of the tube. On returning to the initialposition shown in Figure 1, the die rollers engage a new part of thetube and immediately thereafter the next parts d of the supportingrollers engage the die rollers and the above described sequence ofactions is then repeated. At each action the die rollers engage a smallportion of the tube of original diameter, as shown in Figure 1, andreduce it as shown in Figures 2 and 3, and during each return movementof the die rollers a small forward feeding movement is given to the tubeso that the die rollers can engage a new part. Preferably a rotationalmovement ils also given to the tube for the purpose of prev tingformation of, ripples or other arities on the outer surface of the tube.The operation above described is continued until the whole of the tubehas been treated.

In the example shown in Figures 1-3, the die rollers rotate through anangle of about 120, the amount of rotation during each lateral movementbeing dependent on the length of each working part d of the supportingrollers. But the amount of angular movement given to the die rollers maybe varied by appropriate alteration of the length of the vparts d.' Whenit is required to impart a larger angular movement to the die rollersthan is shown in Figures 1-3, the length of the parts d on thesupporting rollers is correspondingly increased.

By treating tubes in the manner above described I am able to effectlarge reductions of diameter and thickness in a very rapid andeconomical manner.

I will now describe a. complete machine embodying my invention.Referring first to Figures 4 and 5 I mount upon a base i a pair ofhousings k provided with bearings l for the upper and lower supportingrollers c. Between these rollers are arranged the die rollers a whichare carried upon a reciprocatory carriage m. The supporting rollers care interconnected by gear wheels n and one of them is connected to agear wheel o which is driven by a gear wheel p from any convenientsource of motion. At one side of the housings Ic is arranged ahorizontal framework q on which is mounted mechanism for impartinglongitudinal feeding and rotational movements to the tube. Also there isarranged at the other side of the housings k a mechanism for supportingand rotating the forward end of the tube. It will be convenient todescribe separately each of the main functional parts of the machinewhich are shown assembled in Figures 4 and 5, and this will be done withreference to the drawings shown in Figures 6 to l0.

Referring to Figures 6 and 7, the carriage m on which are mounted thedie rollers a is carried on horizontal guide rods r and is freelyslidable thereon. The carriage is moved towards the right of Figure 6 bymeans of a pair of strong springs s. These springs are anchored at theirforward ends to the carriage and at their rear ends to the frame q abovementioned. In Figure 6 the carriage is shown for. convenience in itsforward position wherein the springs s are extended. As soon as the dierollers a are released by the supporting rollers c the springs s retractthe carriage and the die rollers to the position relatively to therollers c shown in Figure 1. It will be understood that the die rollersa are free to slide 'relatively to each other in the vertical directionon the carriage m, the movement of the die rollers towards each otherbeing effected by the supporting rollers c in the manner abovedescribed, and the movement of the die rollers away from each otherbeing effected by their rolling up the tapered part of the tube underthe action of the springs s when released by tbe supporting rollers.

To keep the die rollers a. in proper angular relationship with eachother I secure to one end of each die roller a radial arm t and to theouter end of each arm I pivotally connect one end of a link u. The otherends of the links u are pivoted to the opposite ends of a cross bar vwhich at its centre is connected to a spring w anchored to the frame ofthe machine. During the forward travel of the carriage this spring w isextended and during the return of the carriage the spring w by itsaction on the rollers a through the parts t, u., v, ensures that therollers a shall commence each successive squeezing and reducing actionin the proper angular relationship shown in Figure 1.

The intermittent feeding forward of the tube is effected by themechanism shown in detail in Figures 8, 9 and 10. Referring to thesefigures, and particularly to Figures 8 and 9, there is mounted upon theframe q above-mentioned a carriage 2 which is supported on the frame qby rollers 3 which latter can roll along the upper horizontal side ofthe frame. On this carriage is` ward end of the screw is supportedby theright mounted a rotatable hollowmember 4 through which can pass themandrel rod 5 and at the front end of which is mounted a chuck forgripping the rear end of the tubel g. This chuck comprises a splitconical gripping piece 6 which can be caused to grip the tube g by theaction of an annular wedge 1. This latter is moved into the operativeposition by an internal bush 8 which is acted on by bell crank levers 9the latter being movable by i a. sliding sleeve- I which isvactuated bya hand lever II. The hollow body 4 is rotatably supported on thecarriage 2 by bearings I2 and it is rotated by 'means of agear wheel I3secured to the rear end of the said hollow body 4. The gear wheel I3engages with another gear wheel I4 (Figures 5, 8 and 9) which wheel isin feather-key connection with a longitudinal shaft I for impartingintermittent rotational movements to the tube. Intermittent longitudinalmovements are given to thecarriage 2 by a screw I6.

The mandrel rod 5 must be free to rotate with the tube. although itreceives no longitudinal movement during the normal working of themachine. To satisfy this-condition the rear end of the rod 5 is anchoredto a carriage I 1 supported by rollers I8 on a track 60 at the rear ofthe frame q.

'Ihe connection between the rod 5 and the cartrack 60. For this purposea vertical plunger 55` slidably supported in a fixed bracket 56 isadapted at its lower end to pass through an aperture in a cross member51 of the carriage I1 and enteran aperture in the lower part ofthebracket 56. A pinion 58 engaging teeth formedin one side of the plunger55 is adapted to be actuated by a hand wheel 59 to move the plunger intoand out of its locking position. o enable the mandrel to be insertedwithin a n w tube length the carriage I1V is released from the track 65by appropriate movement of the hand wheel 59 and then moved backwardsalong the track. After the tube and mandrel have been brought togetherthe carriage is returned to its forward position for the purpose ofbringing the forward end of the tube between the die rollers, and isthen locked by the plunger 55.

The rotational movement of the shaft l5'and screw I6 is effected by themechanism shown in Figures 4, 5, `8 and 10. On the driving shaft :I:which carries the pinion p above mentioned there is secured a bevelpinion 6I 'gearing with another bevel pinion 26. 'I'his latter issecured to a short shaft 2l carried by bearings 22, and on one end ofthis shaft 2l is secured a disc 23 vfrom one side of which extends aroller 24.

The 'roller 24 is adapted to engage` each in succession of a number ofradial slot 25 in the disc 26, secured to a shaft 21 arr n ged` in linewith one end of the s aft I5 The two shafts 21 and I5 can be coupleogether by a clutch 28 which can be operated by a lever*29. By means ofthis mechanism the continuous vrotation of the shaft 2| is convertedinto ,intermit-l canbe adjusted or released by a screwed stem handbearing 22 shown in Figure 10. To hold the shaft I5 stationaryduring theintervals between the intermittent rotary movements the disc 23 isprovidedon one side with a disc-like boss 30jiwhich can engage concaverecesses formed in the periphery of the disc 26 between the radialnotches 25. During the engagement of the roller 24 with a radial groovein the disc 26 the required rotation of the latter is permitted bya'concave recess 3l formed in an appropriate part of the periphery ofthe boss 30. ATo enable the carriage 2 to return quickly to its rearposition the nut 32 which connects the carriage to the screw IiiV ismade in two parts which can be separated by a hand lever 33 acting,through a link 34 and lever 35, on any convenient cam mechanism, suchas, a rotary disc 64 connected to the lever 35 and having cam slotsengaging pins 65 on the parts of the nut 32. f

To support the relativelyslender forward end of the tube I providel thesupport shown at the left hand side of Figures 4, 5 and 6, and to avoidthe imposition of undesirable torsion on the supported, part of the tubethe said support is made to rotate at the same rate as the tube.YReferring to Figure 6 it will be seen that the support comprises` aplurality of friction pieces 36 which bear'upon the exterior of the tuberand form the pas's through which the tube can slide. These frictionpieces are carried in a rotatable ring 31 which is supported in a fixedhousing 38. The pieces 36 are heldin frictional engagement with the tubeby an annular and rotatable wedge piece 39 which is held in itsoperative y position by a leverv40 which is loaded by a spring p Thepressure of the spring on the-lever 49 42 carrying the spring andengaged byan internally -screw threaded hand wheel 43. The intermittentrotation of the ring 31 Vis obtained from the shaft 21 above described.As will be seen in Figures 4 and 10, one end of this shaft has securedto it a bevel pinion 44 engaging another bevel pinion 45 on a shaft 46and this vlatter transmits its motion through other bevel pinions 41, 49to a shaft 49 o n which is secured a wheel 50 gearing with a wheel 5I(Figure 5). The wheel 5I is secured to a sprocket wheel 52 whicl'bymeans of a chain 53 is connected to a sprocket wheel 54 secured to thering l31 thus imparting a rotational motion to the supporting pieces 36at the same rate as the rotational motion imparted to the tube.

The support above described also serves an additional purpose. When vthetube.v undergoing treatment approaches the end of the reducingoperation, and can no longer be fed forward by y the mechanism shown inFigure 9, the machine is stopped and the tube is detached from thegripping pieces 6 of the chuck. Another tube to be reduced is thenplaced on the rod 5 and secured by the said pieces 6, the forward end ofthis tube being arranged to bear against the short rearl end of`the'tube still in the machine.

The latter tube is fed forward intermittently by-` the pressure of thesecond, but seeing that it is no longer connected to the chuck grippingpieces 6, it has to be rotated by some other means, and \this functionis` performed by the mechanism above described and shown in Figure 6.

The invention is not limited to the example above described assubordinate mechanical details may be varied. Thus instead o fintermittently releasing the die'rollers by arranging flats on thesupporting rollers I may provide means acting on the supporting rollersfor intermittently releasing their pressure on the die rollers.

Further instead of effecting the return of the die roller carriage bymeans of a spring as above described it may be returned by a weight, or

b y any convenient lever, cam or other mechanism suitably co-ordinatedwith the supporting rollers, butin all cases the die rollers arereciprocated relatively to the work piece and the supporting rollers,and their rotational -movements are derived from the supporting rollers.Moreover, the required co-ordination of the die rollers can be effectedby lnterengaging gear wheels mounted on the ends of these rollers,though the spring and linkage mechanism above described is preferred onaccount of its simplicity and convenience.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:-

l. A machine for effecting reducing operations on tubes or rods,comprising the combination of die rollers forming the pass through whichthe work piece is to travel, driven supporting rollers which also serveto rotate the die rollers and to move them along the work piece, andmeans for returning the die rollers to their initial positionsindependently of the 'driven supporting rollers when the latterassume'predetermined positions.

2. A machine for effecting reducing operations on tubes or rods,comprising the combination of die rollers forming the pass through whichthe work piece is to travel, a reciprocatory carriage on which the dierollers are mounted, driven supporting rollers formed around theirperipheries with alternately arranged working surfaces and inactivesurfaces` and means acting on the carriage for imparting rearwardmovements to the die rollers when they coincide with the inactivesurfaces on the supporting rollers, the movements of the die rollers andcarriage in the forward direction being effected, when thev machine isin operation, by the action of the working surfaces of the supportingrollers on the die rollers.

3. A machine for effecting reducing operations on tubes or rods,comprising the combination of a pair of die rollers forming the passthrough which the work piece is to travel, a reciprocatory carriage onwhich the die rollers are mountedso as to be freely movable towards andaway from each other, a pair of driven supporting rollers acting onopposite sides respectively of the die rollers and each formed aroundits periphery with alternately arranged working surfaces and inactivesurfaces, -gearing interconnecting the supporting rollers, means foreffecting relative co-ordination of the die rollers, and means acting onthe carriage for imparting rearward movements to the die rollers whenthey coincide with the inactive surfaces on the supporting rollers, themovements of the die rollers and carriage in the forward direction beingeffected, when the machine is in operation. by .the action of theworking surfaces of the supporting rollers on the die rollers.

4. A machine for effecting reducing operations on tubes' or rods,comprising the combination of die rollers each formed with a peripheralgroove which varies in width progressively from a narrow partcorresponding approximately with the diameter to be produced on the workpiece to a relatively wide part corresponding approximately with theoriginal diameter of the work piece, the die rollers being arranged sothat their peripheral grooves co-operate to form the pass through whichthe work piece is to travel, driven supporting rollers which also serveto rotate the die rollers, and means for effecting reciprocatorymovements of the die rollers relatively to the work piece and supportingrollers.

5. A machine for effecting reducing operations on tubes or rods,comprising the combination of die rollers each formed with a peripheralgroove which varies in width progressively from a narrow partcorresponding approximately with the diameter to be produced on the workpiece to a relatively wide part corresponding approximately with theoriginal diameter of the work piece, the die rollers being arranged sothat their peripheral grooves co-operate to form the pass through whichthe work piece is to travel, a reciprocatory carriage on which the dierollers are mounted, driven supporting rollers formed around theirperipheries with alternately arranged working surfaces and inactivesurfaces, and means acting on the carriage for imparting rearwardmovements to the die rollers when they coincide with the -inactivesurfaces on the supporting rollers, the movements of the die rollers andcarriage in the forward direction being effected, when the machinev isin operation, by the action of the working surfaces of the supportingrollers on the die rollers.

6. A machine for effecting reducing operations on tubes or rods,comprising the combination of a pair of die rollers each formed with aperipheral groove which varies in width progressively from a narrow partcorresponding approximately with the diameter to be produced on the workpiece to a relatively widepart corresponding approximately with theoriginal diameter of the work piece, the die rollers being arranged sothat their peripheral grooves co-operate to form the pass through whichthe work piece is to travel, a reciprocatory carriage on which the dierollers are mounted so as to be freely movable towards and away fromeach other, a pair of driven supporting rollers acting on opposite sidesrespectively of the die rollers and'each formed around its peripherywith alternately arranged working surfaces and inactive surfaces,gearing interconnecting the supporting rollers, means for effectingrelative co-ordination of the die rollers, and means acting on thecarriage for imparting rearward movements to the die rollers when theycoincide with the inactive surfaces on the supporting rollers, themovements of the die rollers and carriage in the forward direction beingeffected, when the machine is in operation; by the action of the workingsurfaces oi' the supporting rollers on the die rollers.

'7. A machine for effecting reducing oprations on tubes or rods,comprising the combination of a pair of die rollers each formed with aperipheral groove which varies in width progressively from a narrow partcorresponding with the diameter to be produced on the work piece to arelatively wide part corresponding approximately with the originaldiameter of the work piece, the die rollers being arranged so that theirperipheral grooves co-operate to form the pass through which the workpiece is to travel, a pair of driven supporting rollers which also serveto rotate the die rollers, v means for effecting reciprocatory movementsof the die rollers relatively to the work piece and supporting rollers,a pair of links pivotally connected at their correspondingendsrespectively to the die rollers, these ends being spaced from theaxes of the die rollers, and a spring loaded'member pivotally attachedto the other end of each link and adapted to cooperate with the links tomaintain the die rollers in proper co-relationship.

8. A machine for effecting reducing operations on tubes or rods,comprising the combination of a pair of die rollers each formed 'with aperipheral groove which varies in width progressively from a narrow partcorresponding approximately with the diameter to be produced on the Workpiece to a relatively wide part corresponding approximately with theoriginal diameter of the work piece, the die rollers being arranged sothat their peripheral grooves co-operate to form the pass through whichthe work piece is to travel, a reciprocatory carriage on which the dierollers are mounted, a pair of links pivotally connected at theircorresponding ends respectively to the die rollers, these ends beingspaced from the axes of the die rollers, a spring loaded memberpivotally attached to the other end of each link and adapted toco-operate with the links to maintain the die rollers in properco-relationship, a pair of driven supporting rollers formed around theirperipheries with alternately arranged working surfaces and inactivesurfaces, and means acting on the carriage for imparting rearwardmovements to the die rollers when they coincide with the inactivesurfaces on the supporting rollers, the movements of the die rollers andcarriage in the forward direction being effected, when the machine is inoperation, against the action of the said spring loaded member by theaction of the working surfaces of the supporting rollers on the dierollers.

9. A machine for effecting reducing operations on tubes or rods,comprising the combination of a pair of die rollers each formed with aperipheral groove which varies in width progressively from a narrow partcorresponding approximately with the diameter to be produced on the workpiece to a relatively widepart corresponding approximately with theoriginal diameter ofthe work piece, the d ie rollers being arranged sothat their peripheral grooves co-operate to form the pass through whichthe. work piece is to travel, a reciprocatory spring loaded carriage onwhich the die rollers are mounted so as to be freely movable towards andaway from each other, a pair of links pivotally connected at theircorresponding ends respectively to the die rollers, these ends beingspaced from the axes of the die rollers, a

spring loaded member plvotally attached to the other end of each linkand adapted to co-operate with the links to maintain the die rollers inproper co-relationship, a pair of driven supporting rollers acting onopposite sides respectively of the die rollers and each formed aroundits periphery with alternately arranged working surfaces and inactivesurfaces, gearing interconnecting the supporting rollers, the movementsof the die rollers and carriage in the forward direction being eifected,when the machine is in operation, against the action of the springloadings by the action of the working surfaces of the supporting rollerson the die rollers, and the rearward movements oi the carriage beingeffected by the spring loadings.

10. A machine for effecting reducing operations on tubes or rods,comprising the combination of die rollers forming the pass through whichthe work piece is to travel, a reciprocatory carriage on which the dierollers are mounted, driven supporting rollers formed around theirperipheries with alternately arranged working surfaces and inactivesurfaces, means acting on the carriage for imparting rearward movementsto the die rollers when they coincide with the inactive surfaces on thesupporting rollers, the movements of the die rollers and carriage in theforward direction being effected, when the machine is in operation, bythe action of the working surfaces of the supporting rollers on the dierollers, a

carriage for the work piece, means for imparting intermittentlongitudinal feeding movements to the work piece carriage. a chuck onthe work piece carriage for gripping the work piece, and means forimparting rotational movements to the chuck simultaneously with thefeeding movements of the Work piece carriage.

11. A machine as claimed in claim 10 and comprising a mandrel-supportingrod, a carriage to which the rear end of the said rod is rotatablyconnected, and locking means for detachably securing the latter carriageagainst endwise movement.

12. A machine as claimed i-n claim 10 and comprising a rotationalsupport for the forward end of the work piece, and means for impartingrotational movements to the said support concurrently with therotationalmovements imparted to the chuck on the work piece carriage.

ALBERT NORTON.

